Alpha-adrenergic blockade in the diagnosis of detrusor instability secondary to infravesical obstruction

Detrusor instability secondary to infravesical obstruction is probably caused by overactive stretch receptors in the bladder wall. Since recent studies have shown that alpha-adrenergic blockade with phenoxybenzamine reduces the intravesical pressure under micturition, we undertook this investigation in order to see if phenoxybenzamine has an effect on detrusor instability caused by infravesical obstruction. We found that the detrusor instability was abolished by phenoxybenzamine, which supports the 'stretch receptor theory'. Further, phenoxybenzamine is probably a good test in the diagnosis of detrusor instability secondary to infravesical obstruction.